This study focuses on neurobehavioral correlates of maternal cocaine use. Specific aims are: to determine extent of cocaine use in a non-clinical sample; to assess the physical and behavioral status of exposed and unexposed newborns (first 2 days of life) and to evaluate biobehavioral/cognitive development through 26 months. A hospital screening study at 3 hospitals over 2 years will yield data about drug use/health care during pregnancy for 8000 women. From this group, 480 while mother-infant pairs will be selected: (a) 120 cocaine (COC) only; (b) 120 COC + MAC (marijuana, alcohol and/or cigarettes (c) 120 MAC only; & (d) 120 no COC or MAC. Users of other illegal drugs will be excluded Validity of self-reported drug use will be assessed with a urine screen on a sample of 400 mothers as well as all newborns in the follow-up study. Maternal variables and postnatal variables will be included in multivariate analyses to adjust for group differences. Dose-response effects will be assessed. A battery of assessments has been refined by this team of behavioral teratologists and developmental psychologists. Prior research indicates that these technically sophisticated measures (compared to conventional or clinical ones) are sensitive indicators of CNS dysfunction theoretically attributable to intrauterine conditions. The behavioral battery includes: direct observation of newborn behavior; electronic measures of sucking; quantitative indices of newborn activity; measures of Circadian rhythms during the first 4 months of life; and 2 methods for testings visual acuity and recognition memory. The latter is hypothesized to be a precursor of higher order cognitive processes (and predicts later IQ). Biological measures include: dysmorphologic signs, anthropomorphic measurements, medical status at birth and during hospital stay, infant illnesses, mental and motor development, and language development. All data will be collected without knowledge of exposure history or previous test performance. Pilot studies have indicated that recruitment procedures are feasible and that the screening population will be adequate for the anticipated size of the follow-up study. The rapid increase in women's cocaine use is alarming. To our knowledge, this is the first study of offspring effects of maternal cocaine use in general (non-addicted) population of primarily middle-class mothers. The proposal includes caveats about limitations inherent in a single human study, yet the need for objective data is recognized.